I don’t think anyone is disagreeing that they were influential....but influential doesn’t mean great, just as popular doesn’t mean great. Kevin Costner is very popular, not a great actor by any means.
I think that how long the popularity lasts may inform how good the band or the actor is. Kevin Costner was very popular for awhile. Not as much anymore. If people decades down the road like the actors even though they were too young to be the target audience at the time or maybe even weren't born yet, then that's a sign that the actor was good in a more timeless sense.
Beatles music by and large stands up today. People that didn't exist when it was made like it. Think of other bands that were really big in the 60s or 70s or 80s and think how well their music stands up today. Some does but a lot more doesn't
There's plenty of older music that I listen to and think "I can't believe that music was so popular back then" but Beatles music isn't among it.